test: disable broken test for 1.10

This test was added recently as a regress test for the spec relaxation
in #9060, but doesn't work correctly yet. Disable for now to fix noopt
builders.

Updates #22444.

Change-Id: I45c521ae0da7ffb0c6859d6f7220c59828ac6149
Reviewed-on: https://go-review.googlesource.com/81775
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

test/method7.go

@@ -45,9 +45,8 @@ func main() {
 	interface{ m1(string) }.m1(x, "d")
 	want += " m1(d)"
 
-	g := struct{ T }.m2
-	_ = g
 	// cannot link the call below - see #22444
+	// g := struct{ T }.m2
 	// g(struct{T}{})
 	// want += " m2()"